System and method for cutting to length long rolled products coming from different strands of a rolling mill

ABSTRACT

A system for cutting to length at least two strands of long rolled products ( 3, 5 ) preferably coming from a hot rolling mill, the system includes shears comprising at least two rotatable drums ( 4,6 ), each drum having a cutter ( 8,8′,10,10′ ) arranged to cut simultaneously at least two strands of long rolled products into finished segments. At least two movable guides( 12,14 ), each including at least two channels, each guide arranged to receive and guide at least one strand ( 3,5 ) of long product, the guides being movable between a position wherein, in operation, the strands of long product are located in positions either outside of the trajectory of the cutters in a position wherein the strands cannot be cut or wherein the strands are located on the trajectories of the cutters and can be cut by the cutters.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a 35 U.S.C. §§371 national phase conversionof PCT/EP2014/063486, filed Jun. 26, 2014, which claims priority ofEuropean Patent Application No. 13425096.8, filed Jul. 5, 2013, thecontents of which are incorporated by reference herein. The PCTInternational Application was published in the English language.

BACKGROUND OF THE INVENTION

The invention concerns a system for cutting to commercial length ferrouslong rolled products coming from different strands of a rolling mill.

The invention may be used particularly, but not exclusively, inhot-rolling plants for the production of ferrous long products such asbars, rods or the like.

In order to produce finished long metal products such as bar, rod or thelike, a plant comprises, among other devices, a plurality of rollingstands aligned along a rolling line to continuously roll billetsreceived from a furnace or other like source.

A long product production plant can be configured to processsimultaneously a plurality of strands. The strands are obtained bydividing or slitting the product when it is still hot at a given pointof the plant, for example after a given number of rolling passes. Theslitting is to increase the production rate of a plant withoutincreasing the rolling speed of the last stands. After this slitting,the long metal product is divided in different strands which need to besubsequently treated.

After the last rolling stand, the product is generally cut into barsegments, which are subsequently cooled, for example in a cooling bed.

Therefore, there is a need for a simple, compact and efficient cuttingmeans able to cut a plurality of strands coming from a rolling millbefore their discharge onto a cooling bed.

SUMMARY OF THE INVENTION

The above mentioned problems are solved by a system for cutting tolength at least two strands of long rolled products preferably comingfrom a hot rolling mill[.] The system comprises:

a shear comprising at least two rotatable drums, each drums havingcutting means arranged to simultaneously cut at least two strands oflong rolled products into finished segments,

at least two movable guides, each guide comprising at least twochannels, each channel being arranged to receive and guide at least onestrand of long product[:] the guides are movable between a positionwherein, in operation, the at least two strands of long products arelocated outside of the trajectory of the cutting means in a position atwhich the strands cannot be cut, and a position at which the at leasttwo strands are located on the trajectory of the cutting means and canbe cut by the cutting means.

According to other features of the invention, taken alone or incombination:

each drum comprises at least two knives spaced apart from each other andextending outwardly from an external wall of the drum;

the knives of a drum have substantially circular trajectories, eachtrajectory is contained in parallel vertical planes;

at least one knife of each drum is located such that its circulartrajectory is contained in one vertical plane;

each drum comprises one knife, each knife has two cutting surfaces andhas a “U” shape defining a passage for one or more strands;

the guides are rotatable between two positions;

each guide comprises a spacer extending between each channel andhorizontally spacing apart each channel relative to the other channel ofthe guide;

each drum has a substantially cylindrical shape with an axis, each axisis located in the same vertical plane and extends in a parallel mannerone relative to the other;

the knives of each drum are aligned on a line parallel to the axis ofsaid drum;

The system comprises a plurality of driving means, each connected to aconnector of a guide and each driving mean comprising a crank andconnecting rod assembly intended to cyclically translate eachcorresponding guide in two directions.

each guide further comprises a shaft connected to the two channels,wherein the translation provokes rotation of each guide about the shaftbetween said two positions;

a first guide is located upstream the of shear and a second guide islocated downstream the of shear in the travel direction of the strands.

The invention also concerns a method of cutting to length at least twostrands of long rolled products into finished segments , said at leasttwo strands preferably coming from a hot rolling mill[.] The methodcomprises:

continuously moving the two strands forward,

simultaneously guiding the at least two strands within the trajectory ofcutting means able to simultaneously cut the at least two strands ,

simultaneously cutting the at least two strands with the cutting means,

simultaneously guiding the at least two strands outside the trajectoryof the cutting means.

Advantageously the guiding steps comprise simultaneously rotating thetwo strands.

The invention provides a system for cutting to length long rolledproducts coming from different strands of a rolling mill simultaneouslyand in a simple manner and also minimizing the space needed to processmultiple strands in a rolling mill plant.

BRIEF DESCRIPTION OF THE DRAWINGS

The teachings of the present invention can be readily understood byconsidering the following non-limiting detailed description inconjunction with the accompanying drawings, in which:

FIG. 1 is a schematic view of a cutting system according to theinvention.

FIG. 2 is a schematic top view of a guide used in the cutting systemshown in FIG. 1;

FIG. 3 is a longitudinal cross section of a possible embodiment of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

In the embodiment of FIGS. 1 and 2, the system for cutting to lengthlong rolled products according to the invention comprises an upper drum4 and a lower 6 drum. Each drum 4 or 6 has a substantially cylindricalshape with a respective axis X or X′ and each supports cutting meansarranged to cut simultaneously two strands of long products coming froma rolling mill or from another source into finished segments. The axes Xand X′ are located in the same vertical plane and extend parallel withinthe plane.

As shown in the FIGS. 1-3, the cutting means may be knives supported bythe drums 4 and 6. Each knife extends radially outwardly from theexternal wall of its respective drum 4 or 6. In this embodiment, eachdrum 4 or 6 supports a pair of upper knives 8, 8′ or a pair of lowerknives 10,10′, respectively . Within each pair, the knives are axiallyaligned and axially spaced apart one relative to the other[.] Thedistance between the knives depends on the distance between the twostrands of products. In other words each upper knife 8 and 8′ is atleast partially located in a plane passing through the axis X of itsdrum 12 and each lower knife 10 and 10′ is at least partially located ina plane passing through the axis X′ of its drum 14. Furthermore, lowerand upper knives are horizontally spaced apart within their planes.Again, the knives of each drum 8/8′ or 10/10′ are aligned parallel tothe axis of the drum and are spaced apart on this line.

The pairs of knives 8/8′ and 10/10′ rotate with their respective drumand are positioned such that two sections from two strands aresimultaneously cut. Each upper knife 8, 8′ cooperates with a respectivelower knife 10 or 10′ to cut a strand of long product into finishedsegments. In the embodiment shown in the Figures, an upper knife 8 and alower knife 10, called here left knives, which are intended to cut onestrand of long product, are located at least partially in a first radialplane relative to the axes X,X′. In the same manner, the other upperknife 8′ and lower knife 10′, called here right knives, are located atleast partially in a second radial plane relative to the axes X,X′.

The right and left knifes are located to overlap when they reach a pointwhere their circular trajectories are closer (for example the lowerpoint for the upper knives 8,8′ and the upper point for the lower knives10,10′) in order to cut the strand 3 and 5 of long product in finishedsegments of rolled long product.

Drums 4 and 6 are connected to one or a plurality of driving mean(s)(not shown) which rotate(s) both drums at the same peripheral speedregardless of drum diameter. As shown on FIG. 3, the driving means maycomprise a gearbox/motor assembly 28.

The system also comprises at least two rotatable guides 12 and 14. Eachguide comprises two channels[.] Each channel is configured, intended andarranged to receive and to guide one strand of long product. As can beseen in all the Figures, an entry guide 12 extend horizontally upstreamof the shear 7 in the direction of travel of the product and an exitguide 14 extends horizontally downstream of the shear 7.

The channels 12 a/12 b or 14 a/14 b of a respective guide 12 or 14 maybe spaced apart and linked together by means of at least one spacer 12 cor 14 c. A rotation rod (or shaft) 12 d or 14 d extends vertically downfrom each of the spacers 12 c or 14 c. Each channel 12 a or 12 b maycomprise an entry section having a conical shape[.] The entry sectionleads to an exit section having a constant cross-section intended tomaintain each strand in the correct position before and after theshearing.

Guides 12 and 14 are spaced apart by a distance sufficient for theknives to cooperate to cut the respective strands and at the same timeto allow a correct guiding of the strands and of the segment of strandsbefore and after cutting.

As seen in FIG. 3, driving means can be provided to rotate thecorresponding guide about each rod 12 d or 14 d. The driving means canbe connected to a connector 16 or 18 located on the side of each guide12, 14. In the embodiment shown, each driving means comprises a crankand a connecting rod assembly 20 or 22 which is driven by a motor 24 or26. Each assembly comprising driving means and a guide forms a four barslinkage system.

Each assembly 20, 22 when activated cyclically translates itscorresponding guide 12 or 14 forward and backward. The guides 12 and 14are in turn rotated about their shaft 12 d or 14 d, between a noncutting position wherein, in operation, the strands of long products 3or 5 are located outside of the trajectory of the cutting means in aposition wherein the strands cannot be cut and, a cutting positionwherein the two strands 3 and 5 are located on the trajectory of thecutting means 8, 8′ and 10, 10′ where the strands can be cut by thecutting means into segments of long product. FIGS. 1 and 2 show aconfiguration where the strands 3 and 5 are outside the cuttingtrajectory. The travel range of a guide 12 or 14 is materialized in FIG.2 by the double arrow A.

To cut both strands 3 and 5 into finished segments, drums 4 and 6 arecontinuously rotated, in opposite directions. It has to be noted thatthe two strands of product are continuously moved forward by pinch rolls(not shown) located upstream and/or downstream of the system accordingto the invention.

In the embodiment shown in FIG. 2 the driving means of the guides arecontrolled, in a first step, such that in a non-cutting position the twostrands are outside of the trajectory of the cutting means with onestrand 3 located between the left cutting means 8 and the other strand 5located on the right side of the right cutting means 8′. Subsequently,in a second step, both strands are rotated (to the left) to bepositioned within the trajectory of the cutting means and are there cutinto segments of long product. Subsequently, in a third step, bothstrands are further rotated to the left such that both strands 3 and 5are again located outside the trajectory of the cutting means. Here, theleft strand 3 is located on the left side of the left cutting means 8and the right strand 5 is located between the two cutting means.Thereafter, in a fourth step, both strands are driven back into thetrajectory of the cutting means and are again cut into segments of longproduct. The cycle is then repeated from the first step.

These motions are illustrated by the double arrow labeled A which showsthe travel of the center line CL of the guide 12.

In another embodiment, in a first step, guides 12 and 14, each fed withrolled long products by an upstream pinch roll, are driven to positioneach strand 3 and 5 on the circular trajectory of the right 8′/10′ andleft 8/10 pair of knives. Therefore, at the end of this rotation eachstrand 3 and 5 is respectively located between the knives 8/10 and8′/10′of the left and right pair of knives.

This motion of the guides is illustrated for example by the double arrowlabeled A on FIG. 2.

Further rotation of the drums 4 and 6 causes an overlapping of theknives 8′/10′ forming the right pair of knives and also provokes andoverlapping of the knives 8/10 forming the left pair of knives andprovokes cutting of both strands 3 and 5 simultaneously.

Subsequently, in a second step, each guide 12 or 14 is rotated into aposition where the strands 3 and 4 are located outside the circulartrajectory of the knives. For example, and as seen on FIG. 2 which showsa top view of FIG. 1 wherein only knives 8, 8′ or 10, 10′ arerepresented, the strand guides are rotated in clockwise direction untila point where strand 3 is located between knives 8 and 8′ (respectively10, 10′) whereas the strand 5 is located on the left hand side of theknives 8′ and 10′.

As above described, the motion of each strand 3 and 5 is limited to theminimum needed to displace each strand from a position where each strandis outside the trajectory of two cutting means to a position where eachstrand intercepts the trajectory of the two cutting means. For thispurpose, the free space between the left and the right knives can beused to position either of strand 3 or strand 5 outside of the cuttingtrajectories.

This also allows the simultaneous cutting of both strands, whichsimplifies the subsequent handling of the segments.

Subsequently second and third steps are repeated such that pluralitiesof segments are cut to length from both strands simultaneously.

Control means (not shown) synchronize the different driving elements ofthe system according to the invention such that to operate the cut ofeach strand of long product, for example, by controlling the speeds ofthe motors 24 and 26, the speed of the motor part of gearbox/motorassembly 28, and the speed of the strands of long products via the speedof the driving pinch rolls. The position of the knives can also beprovided to the control means by appropriate sensors, in order torealize the position regulation. The control means also control theabove mentioned parameters to obtain the desire length of the longproduct segments.

It has also to be noted that the driving means can be driven such thatboth strands of the long product travel cyclically from the right sideof the cutting means until the left side of the cutting means. This canbe for example the case in an embodiment wherein only one knife isprovided per drum for cutting a plurality of strands of long products.

In another embodiment (not shown) each drum comprises only one knife.Each knife has two cutting surfaces and has a “U” shape defining apassage for one or more the strands. In this embodiment, each knife maycomprise two ends similar to the knives 8 and 8′, said ends beingconnected together with a further horizontal portion extendingtherebetween. In this embodiment, the upper knife has an inversed “U”shape, whereas the lower knife has a “U” shape.

As above shown, the invention provides an efficient and compact mean tosimultaneously cut a plurality of strands coming from a hot rollingmill.

1. A system for cutting to length at least two strands of long rolledproducts coming from a rolling mill, the system comprising: a shearcomprising at least two rotatable drums, each drum having cuttingdevices arranged to simultaneously cut the at least two strands of thelong rolled products which are passing the drums, into finishedsegments, at least two movable guides, each guide comprising at leasttwo channels, and each channel being located and configured to receiveand guide at least one strand of the long rolled product, the guidesbeing movable between a non-cutting position wherein, during operationof the system, the at least two strands of long products are locatedoutside of a trajectory of the cutting devices and in [] positionswherein the strands cannot be cut, or in cutting positions, whereinduring further operation of the system, the at least two strands arelocated on the trajectories of the cutting devices where the strands canbe cut by the cutting devices.
 2. A system according to claim 1, whereinthe cutting devices of each drum comprises at least two knives forcutting the at least two strands being spaced apart from each other onthe drum and extending outwardly from an external wall of the drum.
 3. Asystem according to claim 2, wherein the knives of each drum havesubstantially circular trajectories when rotating with the respectivedrum, and the trajectories are contained in parallel vertical planes. 4.A system according to claim 3, wherein at least one knife of each drumis located such that its circular trajectory is contained in onevertical plane.
 5. A system according to claim 1 wherein each cuttingdevice includes one knife, each knife having two cutting surfaces andhaving a “U” shape defining a passage for one or more the strands.
 6. Asystem according to claim 1, wherein the movable guides are supported tobe rotatable between the two positions thereof.
 7. A system according toclaim 1, wherein each guide comprises a spacer extending betweenneighboring channels of the respective guide and horizontally spacingapart each channel relative to the other neighboring channel of therespective guide.
 8. A system according to claim 1, wherein each of theat least two drums has a substantially cylindrical shape with an axis,each axis of each of the at least two drums being located in the samevertical plane and extending parallel one relative to the other.
 9. Asystem according to claim 8, wherein the knives of each drum are alignedon a line parallel to the axis of the drum.
 10. A system according toclaim 1, comprising a plurality of driving devices, each driving deviceconnected to a respective connector of a guide, each driving devicecomprising a crank and a connecting rod assembly connected to the guideand configured to cyclically translate each corresponding guide in twodirections.
 11. A system according to claim 10, wherein each guidefurther comprises a shaft connected to said two channels and saidtranslation of the connecting rod assembly provokes rotation of eachguide about the shaft between the two positions.
 12. A system accordingto claim 1, further comprising : [[]]the first guide is located upstreamof the cutting devices and a second guide is located downstream of thecutting devices in a travel direction of the strands.
 13. A method ofcutting to length at least two strands of long rolled products forforming the strands into finished segments, the method comprising:continuously moving the at least two strands forward, simultaneouslyguiding the at least two strands within the trajectories of the cuttingdevices to enable cutting the at least two strands simultaneously,simultaneously cutting the at least two strands with the cuttingdevices[;] and then simultaneously guiding the at least two strandsoutside the trajectory of the cutting devices.
 14. A method according toclaim 13, wherein the guiding step comprises simultaneously rotating thetwo strands.
 15. A system according to claim 1, further comprising arespective driving device for each strand guide configured for movingthe guide relative to the drums, so that the trajectories of the cuttingdevices of the drum are selectively positioned out of or in a path ofthe strands passing the guides.
 16. A system according to claim 15,wherein the at least two strands are supported to run spaced apart pastthe strand guides; the strand guides are located both prior to and afterthe cutting devices, whereby the strands pass the cutting devices andwhen the strands are cut, the cut parts of the strands pass the strandguides after the strands are cut.
 17. A system according to claim 1,wherein the cutter devices on each of the drums are spaced apart leavinga space between the cutter devices.
 18. A system according to claim 17,wherein the driving device is configured to selectively move the strandguides between first positions, at which one of the strands passesbetween two of the cutting devices on the drum, while the other strandpasses outside the trajectory of one of the cutting devices toward whichthe strand guide is then located, and a second position whichselectively returns the strand guides so that the at least two of thestrands are in the trajectories of the cutting devices past which the atleast two strands move.
 19. A system according to claim 18, wherein theat least two strands are supported to run spaced apart past the strandguides; the strand guides are located both prior to and after thecutting devices, whereby the strands pass the cutting devices, and whenthe strands are cut, the cut parts of the strands pass the strand guidesafter the strands are cut. the driving devices for the strand guidesthat both are before and after the cutting devices are operable togetherto move the strand guides toward the same direction to one of the firstpositions and the second position, so that the strands avoid thetrajectories of the cutting devices when the strands move to one of thefirst positions and when the strand guides are returned to the secondposition, the strands can be cut by the cutting devices.